The reason it comes out to positive is because the partial derivative with respect to [itex]t[/itex] of [itex]cos\theta[/itex], should be [itex]-sin\theta[/itex] and then (by the chain rule) the derivative of [itex]{-}{\omega}{t}[/itex] should be [itex]{-}{\omega}[/itex], therefore the two negatives should cancel each other out.

I have a very old edition of Halliday and Resnick that does not involve "that whippersnapper Walker". They use sine rather than cosine for the zeroth derivative. Somewhere along the line they must have switched to cosine for the zeroth derivative and forgotten to adjust the sign of the first derivative accordingly.

I have a very old edition of Halliday and Resnick that does not involve "that whippersnapper Walker". They use sine rather than cosine for the zeroth derivative. Somewhere along the line they must have switched to cosine for the zeroth derivative and forgotten to adjust the sign of the first derivative accordingly.

Staff: Mentor

I have a very old edition of Halliday and Resnick that does not involve "that whippersnapper Walker". They use sine rather than cosine for the zeroth derivative. Somewhere along the line they must have switched to cosine for the zeroth derivative and forgotten to adjust the sign of the first derivative accordingly.

d on how like his "Bible" to introductory physics is the first edition of Fundemanetals of Physics which he says is way more rigorous and advanced (than the 7th edition).

This thread makes me realize how ancient my flatuelence is becoming. My book is plain old Physics, Halliday and Resnick, Third Edition. It predates and is thus more fundamental than Fundamentals of Physics, First Edition.

Staff: Mentor

This thread makes me realize how ancient my flatuelence is becoming. My book is plain old Physics, Halliday and Resnick, Third Edition. It predates and is thus more fundamental than Fundamentals of Physics, First Edition.

I hear you, brother. I have that edition, but actually used an earlier one as an undergrad.

Staff: Mentor

I'm pretty sure I used the 2nd edition, which was copyright 1966. (But god knows where it is*.) I have the new-fangled 3rd edition right here, which claims to be published in 1977. Why can't they leave well enough alone?